1. Field of the Invention
The present invention relates to the field of geographic location systems in general, and specifically, to the use of network access points to provide geographic information.
2. Description of the Background Art
With the proliferation of portable computing devices such as laptop computers and personal digital assistants, and mobile communications devices such as smart phones and cellular telephones, it is advantageous for a user to be able to know their precise location. Knowing one is precise location along with the computational capabilities of such computing devices allows users to access information that can greatly simplify any number of tasks. For example, retrieving directions to an off-site meeting requires knowing your starting point. Similarly, searching for stores, companies, points of interest of interest, etc. requires that the user knows her location. While most present-day computing devices include an ability to communicate wirelessly with other devices or a network, most present-day computing devices do not include any way to determine the location of the computing device.
The prior art has attempted to solve this deficiency by including global positioning system (GPS) circuitry within laptop computers and cell phones. There are currently a number of different companies that manufacture GPS chips for inclusion in such portable computing and mobile communication devices. However, the addition of such global positioning systems to computing devices suffers from a number of deficiencies. First, the additional circuitry can be expensive. For example, GPS devices can range from several hundred dollars to thousands of dollars. Second, GPS devices typically needed a significant amount of time to acquire position signals from satellites as well as perform the calculations necessary to determine location. For example, an initialization of the GPS circuitry can take several minutes. Even when the GPS device active, it takes a minimum of 35 seconds to establish the initial location of the computing device. Finally, the greatest disadvantage with GPS systems is that they do not function properly inside office buildings and in high density urban environments. The physical structure of the office buildings interferes with the position signals from the satellites which are sensitive to timing differences caused by signal bounces, and are too weak to penetrate many structures.
A second prior art approach uses a database of media access control (MAC) addresses and offers this information over a network such as the Internet as a location-based service. The database includes pairs of locations and MAC addresses. The pair information in the database is determined by hiring drivers in most major cities to map the MAC addresses of access points to locations in their city. To determine a location, the user need only retrieve the location corresponding to the access point MAC address from the database. However, this prior art solution also has a number of shortcomings. First, it requires that the user's computing device have a connection to the Internet in order to access the database and retrieve information from it, or have an extensive local database which may be out of date. Second, the location can only be identified to a level of precision of the transmission range of the access point.